Device for securing and tensioning a flexible transfer blanket on a cylinder



Aug. 9, 1955 M. STEMPEL FOR SECURING AND TENSIONING A DEVICE FLEXIBLETRANSFER BLANKET ON A CYLINDER Filed June 4, 1949 NQI INVENTOR LASZLO M.STEMPEL ATTORNEY United States atent DEVICE FOR SECURING AND TENSIONINGA FLEXIBLE TRANSFER BLANKET ON A CYL- INDER Laszlo M. Stempel, New York,N. Y., assignor to Laszlo M. Stempel, New York, N. Y., and AlbertCharles Nolte, Plandome, N. Y., joint trustees Application June 4, 1949,Serial No. 97,295

4 Claims. (Cl. 101-415.1)

The present invention relates to transfer cylinders for applying aprinted or lithographed impression to a web of paper or other material.

More particularly, the invention relates to means for securing andtensioning a flexible transfer blanket which is wrapped around theperiphery of the cylinder.

Arrangements for the tensioning of the flexible transfer blankets areknown in the art, and these generally teach the fastening of one end ofthe blanket within a slot in the cylinder. The free end is then drawninto the cylinder slot adjacent to the end which is already securedtherein. Such tensioning arrangements have the effect of tightening thetransfer blanket about the circumference of the cylinder by means oftension applied to only one end of the blanket. Because of frictionalforces between the inner surface of the blanket and the periphery of thetransfer cylinder, there is a tendency towards eccentricity resultingfrom non-uniformity of the circumferential tension forces in theflexible transfer blanket. Accordingly, it is an object of the inventionto provide a transfer blanket fastening arrangement in which the tensionis applied substantially equally to both ends of the transfer blanket.

A further object of the invention is to provide a recess in the transfercylinder adapted to receive the tensioning devices for both ends of thetransfer blanket, and which will render a minimum portion of thecylinder circumference unusable for printing purposes.

Still another object of the invention is to provide fastening andtensioning members adapted to fit Within a recess in the cylinder, andwhich will effectively close the recess when the blanket is tensionedabout the circumference of the cylinder.

Other and further objects will become apparent upon reading thefollowing specification, together with the accompanying drawing whichforms a part thereof.

The present invention is in the nature of an improvement upon theinvention disclosed and claimed in my copending application, Serial No.33,636, filed June 17, 1948, for Transfer Printing Mechanisms.

In the drawing:

Fig. 1 is a transverse sectional view showing a cylinder,

a blanket, and associated parts embodying features of the invention, thesection being taken along the line 11 of Fig. 4 looking in the directionof the arrows, and the blanket being shown as partially applied;

Fig. 2 is a view similar to Fig. 1, but showing both blanket clampslodged in the cylinder recess and the collars turned to a retainingposition;

Fig. 3 is a view similar to Fig. 2, but showing the collars turned stillfurther to retain the blanket clamps in positions such that the blanketwill be held taut; and

Fig. 4 is a view in sectional elevation, partly broken away, of thetransfer cylinder of Figs. 1 to 3, the section shown at the left-handportion of Fig. 4 being taken along the line 4-4 of Fig. 3, looking inthe direction of the arrows.

Referring to Fig. 1, a transfer cylinder 11 is provided with alongitudinal slot 12 adapted to receive a pair of 1 bar 14 and acooperative clamping bar 28.

bar members 13 and 14. Slot 12 is so shaped that bar member 14 may firstbe inserted within the slot and pushed to one side, as shown in Fig. l,and the bar member 13 may then be inserted. Collars 15 and 15 areprovided with eccentric recesses 16 and 16, and with apertures 1'7letting into the recesses. The purpose of the collars will be explaineda little farther on. Each of the collars and 15 is shown made in twosections secured together by bolts 18, which serve to assemble eachcollar with capacity for free rotation upon a neck portion 19 ofcylinder 11.

The cylinder 11 is shown with extended shaft portions journalled insuitable bearings 21, the bearings being supported by side walls 22 ofthe printing press or other machine. Suitable provision is made fordriving the transfer cylinder, and for bringing it into engagement withthe printing plate and with the web of material to be printed. Thesefacilities are well-known in the art, and may take any desired form.

A transfer blanket 25 is provided at opposite ends with sets of holes,spaced to conform to the spacing of rivets or screws 26 and 27. Therivets 26 clamp one end of the blanket to the bar 13, while the rivets27 are applied through the opposite end of the blanket and through theThe bars 14 and 28 are located at opposite sides of the blanket, and aredrawn together by the rivets to clamp the blanket between them.

in operation, the bar member 14 is first inserted within the slot 12 asin Fig. 1. The bar member 14 extends beneath an overhanging shoulder inthe recess and is thereby guarded temporarily against accidentaldislodgement. The bar member 13 is then inserted. The condition at thebeginning of the insertion of the bar 13 is also illustrated in Fig. 1.

" posite end portions of the blanket above the bars 13 and 23, and fillsthe remaining width of the slot 12.

The bar 29 is provided at its opposite ends with extensions 31 which arecaused to enter the eccentric recesses 16 and 16 through the apertures17 slightly before the bar 29 reaches the position illustrated in Fig.2. After these end portions have been passed through the opening 17, theeccentric collars 15 and 15 are rotated substantially equally to drawthe ends of the bar member 29 radially inward within the slot 12 towardsthe center of the cylinder.

Since, at this time, the bar member 29 engages both the bars 13 and 23,both ends of the transfer blanket are forced equally into the slot andtowards the center of the cylinder by the bar member 29. The blanket 25is thus drawn snugly around the periphery of the cylinder 11 with atension which is substantially equally applied at both ends of theblanket. Unevenness in tension along the bar members 13 and 28 may beequalized by separate rotation of one of the eccentric collars 15 or 15.

In the final position of the parts, as illustrated in Fig. 3, the barmember 29 is drawn completely within the slot 12, so as not to protrudebeyond the periphery of the cylinder and the blanket.

The bar 29 is formed with an external groove 30 so that a cold chisel orother driving tool placed against it will have no tendency to slide off.

When it is desired to remove a blanket from a cylinder, the collars 15and 15 are first turned to align the openings 17 with the slot 12. Theinner faces of the end portions of the bar 29 are formed with cut-outsor recesses 32, which overlie recessed portions 33 of the cylinder 11. Ascrew driver or other prying tool may be inserted in the notches andused as a lever for starting the bar 29 outward. The bar 29 can then befreely withdrawn and a new blanket can be substituted in an obviousmanner.

I have described what I believe to be the best embodiment of myinvention. I do not wish, however, to be confined to the embodimentshown, but what I desire to cover by Letters Patent is set forth in theappended claims.

I claim:

1. In a transfer press, the combination with a transfer cylinder havinga longitudinal recess therein, and a relatively narrow aperturecommunicating with the recess through the periphery of the cylinder, ofa of bar members shaped to pass individually through the aperture, andto lie side by side and in engagement with each other within the recess,a flexible blanket wrapped around the periphery of the cylinder andsecured at its 1 opposite ends to the respective bar members, a thirdbar member broad enough to substantially fill the aperture space betweenthe blanket ends adapted to be inserted through the aperture and intosimultaneous engagement with the outer faces of the other two barmembers in the recess, and individually adjustable tightening meansdisposed adjacent the respective ends of the longitudinal recess andeach adapted through the third bar to urge the adjacent ends of thefirst and second bars radially inward toward the cylinder insubstantially equal degree.

2. In a transfer press, the combination with a transfer cylinder havinga longitudinal recess therein of uniform cross-section, saidcross-section being shaped to provide a relatively narrow entranceportion through the periphery of the cylinder and an enlarged internalportion, a pair of bar members shaped to pass individually through theaperture and to lie side by side and in engagement with each otherwithin the enlarged portion of the recess, a flexible transfer blanketwrapped around the periphery of the cylinder and secured at its oppositeends to the respective bar members, and a pair of rotatable collars eachmounted adjacent one end of the cylinder and in coaxial relationthereto, and each having a cylindirical opening therein eccentric withrespect to the cylinder, 2. third bar member broad enough tosubstantially fill the aperture space between the blanket ends adaptedto be inserted into the recess between the blanket ends and intosimultaneous engagement with the outer faces of the two bar members,said third bar member having protruding ends insertable into thecylindrical openings of the respective collars, each collar beingarranged upon rotation thereof relative to the cylinder to act throughthe third bar member to urge the associated ends of the other barmembers substantially radially inward toward the center of the cylinderin substantially equal degree.

3. In a transfer press, in combination, a transfer cylinder having alongitudinal recess formed therein, and a relatively narrow aperturecommunicating with the recess through the periphery of the cylinder, ofa pair of bar members shaped to pass individually through the apertureand to lie simultaneously in the recess in engagement with one another,a flexible blanket wrapped around the periphery of the cylinder andsecured at its opposite ends to the respective bar members, a third barmember insertable in the aperture in position to overlie the first twobar members and broad enough substantially to fill the aperture spacebetween the blanket ends, said third bar member when forced inward beingadapted to urge both of the two first-mentioned bar members inwardtoward the center of the cylinder simultaneously and at substantiallythe same rate.

4. In a transfer press, the combination, a transfer cylinder having alongitudinal recess formed therein, a relatively narrow aperturecommunicating with said recess through the periphery of the cylinder, apair of bar members shaped to pass individually through the aperture andto lie simultaneously in the recess in engagement with one another, aflexible blanket wrapped around the periphery of the cylinder andsecured at its opposite ends to the respective bar members, a third barmember insertible in the aperture in a position to engage said pair ofbar members and broad enough so that its width and that of the twoblanket sections substantially fill the aperture space, said third barmember when forced inward being adapted to urge both of the two firstmentioned bar members inward toward the center of the cylindersimultaneously and at substantially the same rate.

References Cited in the file of this patent UNITED STATES PATENTS2,279,204 Neilson Apr. 7, 1942 2,388,193 Stempel Oct. 30, 1945

